The document describes how hills and rocky areas provided advantages for grazing animals over flat plains areas. On plains, heavy rains could turn the ground to mud, trapping herds who were unable to roam freely. This led to disease and other issues. Hills allowed drainage and drying of the ground through convection currents. It's speculated that early humans discovered this and began constructing stone structures like monoliths to provide high ground for livestock, and that these may have developed into early urban centers. Hills thus offered benefits that could have supported the development of civilization.